Update June 21, 2017: Apple has just released watchOS 4 beta 2 for developers. If you already have a previous watchOS 4 beta installed, proceed to the Watch app on your iPhone running iOS 11 and download away. If you were waiting to begin watchOS 4 testing with beta 2, keep reading and we’ll walk you through the set up!
There’s yet to be a public beta for watchOS the way there has been for iOS and macOS, and that’s okay — the process of installing the software is more complicated, and really meant for developers only. You need to install a certificate on your Apple Watch, then download the software to your iPhone running iOS 11 beta, transfer it across, and get it up and running. It’s not hard, but it does take patience and you may have to troubleshoot.
How to download the watchOS 4 beta certificate
How to install watchOS 4 on your Apple Watch
How to downgrade to watch…